Upward continuous casting apparatus and upward continuous casting method

ABSTRACT

An upward continuous casting apparatus includes a molten metal retaining furnace that retains a molten metal, a draw-out part that draws out the molten metal from a melt surface of the molten metal that is retained in the molten metal retaining furnace, a shape-defining member that is located in the vicinity of the melt surface and defines a cross-sectional shape of a casting to be cast by applying an external force to a retained molten metal that has been drawn out by the draw-out part, and a solid heat transfer member that is placed to contact a surface of the casting that is formed through the shape-defining member.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an upward continuous casting apparatus and an upward continuous casting method.

2. Description of Related Art

In Japanese Patent Application Publication No. 2012-61518 (JP 2012-61518 A), a free casting method is proposed by the present inventors as an epoch-making continuous casting method that does not require a mold. As shown in JP 2012-61518 A, when a starter is pulled up after it is immersed into the surface of a metal melt (molten metal) (in other words, the melt surface), the molten metal is also drawn out following the starter by the surface film or surface tension of the molten metal. Here, by drawing out the molten metal through a shape-defining member that is located in the vicinity of the melt surface and cooling the molten metal, a casting with a desired cross-sectional shape can be cast continuously.

In an ordinary continuous casting method, not only the cross-sectional shape but also the longitudinal shape is defined by a mold. In particular, the casting that is produced by a continuous casting method has a shape that is linearly elongated in its longitudinal direction because the solidified metal (in other words, the casting) must be passed through a mold. In contrast, a shape-defining member that is used in a free casting method defines only the cross-sectional shape of the casting and does not define the longitudinal shape of the casting. In addition, because the shape-defining member is movable in directions parallel to the melt surface (in other words, horizontal directions), castings with different longitudinal shapes can be obtained. For example, a hollow casting (in other words, a pipe) that is formed to have a zigzag or spiral, not linear, configuration along its length is disclosed in JP 2012-61518 A.

In the free casting method that is described in JP 2012-61518 A, the unsolidified molten metal that has been pulled up from the melt surface following the starter (retained molten metal) is swung by a cooling medium that is blown out of a cooling nozzle. Thus, in the free casting method that is described in JP 2012-61518 A, it is necessary to prevent the retained molten metal from being swung by lowering the pressure of the cooling medium that is blown out of the cooling nozzle or moving the cooling nozzle away from the retained molten metal. Thus, in the free casting method that is described in JP 2012-61518 A, there is a possibility that the speed at which the starter is pulled up cannot be increased because the solidification rate of the retained molten metal is lowered.

SUMMARY OF THE INVENTION

The present invention provides an upward continuous casting apparatus and an upward continuous casting method in which the speed at which the starter is pulled up can be increased by quickly cooling the casting without swinging the retained molten metal.

An upward continuous casting apparatus according to one aspect of the present invention includes: a retaining furnace that retains a molten metal; a draw-out part that draws out the molten metal from a melt surface of the molten metal that is retained in the retaining furnace; a shape-defining member that is located in the vicinity of the melt surface and defines a cross-sectional shape of a casting to be cast by applying an external force to a retained molten metal which is the unsolidified molten metal that has been drawn out by the draw-out part; and a solid heat transfer member that is placed to contact a surface of the casting that is formed by solidification of the retained molten metal. Thus, the casting can be cooled quickly without swinging the retained molten metal. This allows the speed at which the starter is pulled up to be increased.

The solid heat transfer member may be placed to contact a surface of the casting in the vicinity of a interface between the retained molten metal and the casting.

The solid heat transfer member may have a shape that corresponds to the cross-sectional shape of the casting at a portion of the solid heat transfer member placed into contact with the casting.

The solid heat transfer member may have a curved surface shape at a portion t of the solid heat transfer member placed into contact with the casting.

The solid heat transfer member may have the shape of a circular column that is rotatable in a direction in which the casting is pulled up.

The upward continuous casting apparatus may further include a cooling part through which cooling water is circulated in the solid heat transfer member. The cooling part may have a bucket that scoops up the cooling water as the solid heat transfer member rotates.

The upward continuous casting apparatus may further include a cooling part through which a cooling medium is circulated in the solid heat transfer member.

The upward continuous casting apparatus may further include a cooling nozzle that blows a cooling medium onto an upper surface of the solid heat transfer member.

The upward continuous casting apparatus may further include a supporting member that biases the solid heat transfer member into contact with a surface of the casting.

The supporting member may be a spring.

The solid heat transfer member may have a metal wool at a portion of the solid heat transfer member placed into contact with the casting.

The solid heat transfer member may be made of copper or a copper alloy.

The upward continuous casting apparatus may further include an actuator that moves the solid heat transfer member in response to a movement of the shape-defining member.

When a starter is pulled up from the melt surface, the molten metal may be pulled up from the melt surface following the starter by a surface film or surface tension thereof to form a retained molten metal. A shape may be imparted to the retained molten metal by the shape-defining member. The retained molten metal may be solidified from top to bottom to form a casting.

An upward continuous casting method according to one aspect of the present invention includes the steps of: placing a shape-defining member that defines a cross-sectional shape of a casting to be cast in the vicinity of a melt surface of a molten metal that is retained in a retaining furnace; pulling up the molten metal through the shape-defining member; and cooling the casting by placing a solid heat transfer member into contact with a surface of the casting that is formed by solidification of the molten metal that has been passed through the shape-defining member. Thus, the casting can be cooled quickly without swinging the retained molten metal. This allows the speed at which the starter is pulled up to be increased.

The solid heat transfer member may be placed into contact with a surface of the casting in the vicinity of a interface between a retained molten metal which is the unsolidified molten metal that has been pulled up and the casting.

The solid heat transfer member may have a shape that corresponds to the cross-sectional shape of the casting at a portion of the solid heat transfer member placed into contact with the casting.

The solid heat transfer member may have a curved surface shape at a portion of the solid heat transfer member placed into contact with the casting.

The solid heat transfer member may have the shape of a circular column that is rotatable in a direction in which the casting is pulled up.

A cooling part through which cooling water is circulated may be further provided in the solid heat transfer member, and a bucket that scoops up the cooling water as the solid heat transfer member rotates may be provided in the cooling part.

A cooling part through which a cooling medium is circulated may be further provided in the solid heat transfer member.

A cooling nozzle that blows a cooling medium onto an upper surface of the solid heat transfer member may be further provided.

A supporting member that biases the solid heat transfer member into contact with a surface of the casting may be further provided.

The supporting member may be a spring.

A metal wool may be further provided at a portion of the solid heat transfer member placed into contact with the casting.

The solid heat transfer member may be made of copper or a copper alloy.

The solid heat transfer member may be moved in response to a movement of the shape-defining member.

When a starter is pulled up from the melt surface, the molten metal may be pulled up from the melt surface following the starter by a surface film or surface tension thereof to form a retained molten metal. A shape may be imparted to the retained molten metal by the shape-defining member. The retained molten metal may be solidified from top to bottom to form a casting.

According to one aspect of the present invention, it is possible to provide an upward continuous casting apparatus and an upward continuous casting method in which the speed at which the starter is pulled up can be increased by quickly cooling the casting without swinging the retained molten metal.

BRIEF DESCRIPTION OF THE DRAWINGS

Features, advantages, and technical and industrial significance of exemplary embodiments of the invention will be described below with reference to the accompanying drawings, in which like numerals denote like elements, and wherein:

FIG. 1 is a cross-sectional view that illustrates a configuration example of a free casting apparatus according to a first embodiment;

FIG. 2 is a plan view of a shape-defining member that is provided in the free casting apparatus that is shown in FIG. 1;

FIG. 3 is an enlarged cross-sectional view that illustrates a first modification of the free casting apparatus according to the first embodiment;

FIG. 4 is an enlarged cross-sectional view that illustrates a second modification of the free casting apparatus according to the first embodiment;

FIG. 5 is an enlarged cross-sectional view that illustrates a configuration example of a free casting apparatus according to a second embodiment;

FIG. 6 is an enlarged cross-sectional view that illustrates a first modification of the free casting apparatus according to the second embodiment;

FIG. 7 is an enlarged cross-sectional view that illustrates a second modification of the free casting apparatus according to the second embodiment;

FIG. 8 is an enlarged cross-sectional view that illustrates a configuration example of a free casting apparatus according to a third embodiment;

FIG. 9 is an enlarged cross-sectional view that illustrates a first modification of the free casting apparatus according to the third embodiment;

FIG. 10 is an enlarged cross-sectional view that illustrates a second modification of the free casting apparatus according to the third embodiment;

FIG. 11 is an enlarged cross-sectional view that illustrates a configuration example of a free casting apparatus according to a fourth embodiment;

FIG. 12 is an enlarged cross-sectional view that illustrates a first modification of the free casting apparatus according to the fourth embodiment;

FIG. 13 is an enlarged cross-sectional view that illustrates a second modification of the free casting apparatus according to the fourth embodiment;

FIG. 14 is an enlarged cross-sectional view that illustrates a configuration example of a free casting apparatus according to a fifth embodiment;

FIG. 15 is a cross-sectional view of the free casting apparatus that is shown in FIG. 14 along the line II-II;

FIG. 16 is an enlarged cross-sectional view of a cooling part that is provided in the free casting apparatus that is shown in FIG. 14;

FIG. 17 is a cross-sectional view that illustrates another configuration example of a free casting apparatus according to the present invention; and

FIG. 18 is a plan view of a shape-defining member that is provided in the free casting apparatus that is shown in FIG. 17.

DETAILED DESCRIPTION OF EMBODIMENTS

Description is hereinafter made of specific embodiments to which the present invention is applied with reference to the drawings. It should be noted that the present invention is not limited to the following embodiments. The following description and the drawings are simplified as needed to clarify the description.

<First Embodiment> A free casting apparatus (upward continuous casting apparatus) according to a first embodiment is first described with reference to FIG. 1. FIG. 1 is a cross-sectional view that illustrates a configuration example of a free casting apparatus according to a first embodiment. As shown in FIG. 1, the free casting apparatus according to the first embodiment includes a molten metal retaining furnace (retaining furnace) 101, an external shape-defining member 102 a, a supporting rod 103, an actuator 105, a draw-out part 107, solid heat transfer members 108, and supporting members 109.

The molten metal retaining furnace 101 retains a molten metal M1 of aluminum or an aluminum alloy, for example, and maintains the molten metal M1 at a prescribed temperature. In the example that is shown in FIG. 1, the surface level of the molten metal M1 (in other words, the melt surface) is lowered as the casting proceeds because the molten metal retaining furnace 101 is not replenished with molten metal during casting. However, a configuration in which the molten metal retaining furnace 101 is replenished with molten metal during casting to maintain the melt surface level constant is also possible. It should be appreciated that the molten metal M1 may be a melt of a metal other than aluminum or an alloy thereof.

The external shape-defining member 102 a is made of ceramic or stainless steel, for example, and is located in the vicinity of the melt surface. In the example that is shown in FIG. 1, the external shape-defining member 102 a is placed to contact the melt surface. However, the external shape-defining member 102 a may be located with the principal surface thereof on its lower side (on the side that faces the melt surface) away from the melt surface. Specifically, a prescribed (approximately 0.5 mm, for example) gap may be provided between the principal surface of the external shape-defining member 102 a on its lower side and the melt surface.

The external shape-defining member 102 a defines the external shape of a casting M3 to be cast. The casting M3 that is shown in FIG. 1 is a rectangular column-shaped casting that has a rectangular shape in a horizontal cross-section (which is hereinafter referred to as “transverse cross-section”). More specifically, the external shape-defining member 102 a defines the external shape of the transverse cross-section of the casting M3.

FIG. 2 is a plan view of the external shape-defining member 102 a. The cross-sectional view of the external shape-defining member 102 a in FIG. 1 corresponds to a cross-sectional view that is taken along the line I-I in FIG. 2. As shown in FIG. 2, the external shape-defining member 102 a has a rectangular planar shape, for example, and has a square opening at its center. The opening is a molten metal passing part 102 b through which the molten metal is passed. A shape-defining member 102 is constituted of the external shape-defining member 102 a and the molten metal passing part 102 b as described above.

The draw-out part 107 has a starter (draw-out member) ST that is immersed into the molten metal M1, and a lifter PL (not shown) that drives the starter ST in, for example, vertical directions.

As shown in FIG. 1, the molten metal M1 is joined to the starter ST that is immersed thereinto and then pulled up through the molten metal passing part 102 b following the starter ST with its contour retained by the surface film or surface tension thereof. The molten metal that is pulled up from the melt surface following the starter ST (or the casting M3 that is formed by solidification of the molten metal M1 that has been drawn out by the starter ST) by the surface film or surface tension of the molten metal M1 is herein referred to as “retained molten metal M2.” The interface between the casting M3 and the retained molten metal M2 is a solidification interface.

The starter ST is made of ceramic or stainless steel, for example. The surfaces of the starter ST may be covered with a protective coating (not shown), such as that of a salt crystal. In this case, because melt-bonding between the starter ST and the molten metal M1 can be prevented, the releasability between the starter ST and the casting M3 can be improved. This makes it possible to reuse the starter ST. In addition, the starter ST may have irregular surfaces. In this case, because the protective coating can be easily deposited (precipitated) on the surfaces of the starter ST, the releasability between the starter ST and the casting M3 can be further improved. At the same time, the binding force in the pull-up direction between the starter ST and the molten metal M1 during the draw-out of the molten metal can be improved.

The supporting rod 103 supports the external shape-defining member 102 a. The supporting rod 103 is coupled to the actuator 105.

The actuator 105 has a function of moving the external shape-defining member 102 a up and down (in vertical directions) and in horizontal directions via the supporting rod 103. Thus, the actuator 105 can move the external shape-defining member 102 a downward when the melt surface level is lowered as the casting proceeds. In addition, because the actuator 105 can move the external shape-defining member 102 a in horizontal directions, the longitudinal shape of the casting M3 can be changed freely.

Each solid heat transfer member 108 is made of a metal that has high thermal conductivity, such as copper or a copper alloy, and is placed to contact a surface of the casting M3. More preferably, each solid heat transfer member 108 is placed to contact a surface of the casting M3 in the vicinity of the solidification interface.

The solid heat transfer members 108 are maintained at a temperature that is lower than that of the surfaces of the casting M3 in the vicinity of the solidification interface to cool the casting M3. By cooling the starter ST and the casting M3 with the solid heat transfer members 108 while the casting M3 is being pulled up by the lifter PL (not shown) that has been coupled to the starter ST, the retained molten metal M2 in the vicinity of the solidification interface is sequentially solidified and the casting M3 is formed continuously.

In the free casting apparatus according to this embodiment, the casting M3 is cooled not by a cooling medium that is blown out of a cooling nozzle but by contacting it with the solid heat transfer members 108. Thus, the free casting apparatus according to this embodiment can cool the casting M3 quickly without swinging the retained molten metal M2. This allows the speed at which the starter ST is pulled up to be increased.

In addition, the free casting apparatus according to this embodiment can cool the casting M3 more quickly by contacting the solid heat transfer members 108 with surfaces of the casting M3 in the vicinity of the solidification interface. This allows the speed at which the starter ST is pulled up to be further increased.

The greater the contact area between the solid heat transfer members 108 and the casting M3, the higher the cooling rate of the casting M3. To improve the cooling rate of the casting M3 by increasing the contact area between the solid heat transfer members 108 and the casting M3, the solid heat transfer members 108 may have a shape corresponding to the cross-sectional shape of the casting M3 at a portion of the solid heat transfer member 108 placed into contact with the casting M3, for example. On the other hand, the smaller the contact area between the solid heat transfer members 108 and the casting M3, the smaller the friction resistance therebetween. To reduce the friction resistance between the solid heat transfer members 108 and the casting M3, the solid heat transfer members 108 may have a curved surface shape at a portion of the solid heat transfer member 108 placed into contact with the casting M3, for example.

The supporting members 109 are elastic members, such as springs, which support the solid heat transfer members 108 and bias the solid heat transfer members 108 into contact with surfaces of the casting M3. In this embodiment, a case where the supporting members 109 are springs is described as an example. In this case, because the solid heat transfer members 108 can be moved in response to a change in shape of the casting M3, the solid heat transfer members 108 can be held in contact with the casting M3 and the friction resistance between the solid heat transfer members 108 and the casting M3 can be reduced. The supporting members 109 are coupled to the actuator 105 via a supporting rod, for example. Thus, the solid heat transfer members 108 are movable up and down (in vertical directions) and in horizontal directions together with the external shape-defining member 102 a.

Referring to FIG. 1, a free casting method according to this embodiment is next described.

First, the starter ST is moved downward and immersed into the molten metal M1 through the molten metal passing part 102 b.

Then, the starter. ST starts to be pulled up at a prescribed speed. Here, even after the starter ST is separated from the melt surface, the molten metal M1 is pulled up (drawn out) from the melt surface following the starter ST by the surface film or surface tension thereof and forms a retained molten metal M2. As shown in FIG. 1, the retained molten metal M2 is formed in the molten metal passing part 102 b. In other words, a shape is imparted to the retained molten metal M2 by the external shape-defining member 102 a.

Next, the starter ST and the casting M3 are cooled by the contact with the solid heat transfer members 108. As a result, the retained molten metal M2 is sequentially solidified from top to bottom and the casting M3 grows. In this way, the casting M3 can be cast continuously. It should be noted that the solid heat transfer members 108 may be moved to the vicinity of the solidification interface after the position of the solidification interface is fixed.

As described above, in the free casting apparatus according to this embodiment, the casting M3 is cooled not by a cooling medium that is blown out of a cooling nozzle but by contacting it with the solid heat transfer members 108. Thus, the free casting apparatus according to this embodiment can cool the casting M3 quickly without swinging the retained molten metal M2. This allows the speed at which the starter ST is pulled up to be increased.

Referring to FIG. 3 and FIG. 4, modifications of the free casting apparatus according to this embodiment are next described.

(First Modification of Free Casting Apparatus According to Embodiment) FIG. 3 is an enlarged cross-sectional view that illustrates a first modification of the free casting apparatus that is shown in FIG. 1. Compared to the free casting apparatus that is shown in FIG. 1, the free casting apparatus that is shown in FIG. 3 further includes a cooling part 110 through which a cooling medium, such as water, is circulated in each solid heat transfer member 108. Because the other configurations of the free casting apparatus that is shown in FIG. 3 are the same as those of the free casting apparatus that is shown in FIG. 1, their description is omitted.

Because the free casting apparatus that is shown in FIG. 3 has a cooling part 110 in each solid heat transfer member 108, the solid heat transfer members 108 can be maintained at a temperature that is lower than that of surfaces of the casting M3 in the vicinity of the solidification interface.

(Second Modification of Free Casting Apparatus According to Embodiment) FIG. 4 is an enlarged cross-sectional view that illustrates a second modification of the free casting apparatus that is shown in FIG. 1. Compared to the free casting apparatus that is shown in FIG. 1, the free casting apparatus that is shown in FIG. 4 further includes cooling nozzles 106 that blow a cooling medium (such as air, nitrogen, argon or water) onto the upper surfaces of the solid heat transfer members 108. Because the other configurations of the free casting apparatus that is shown in FIG. 4 are the same as those of the free casting apparatus that is shown in FIG. 1, their description is omitted.

Because the free casting apparatus that is shown in FIG. 4 has cooling nozzles 106 that blow a cooling medium onto the upper surfaces of the solid heat transfer members 108, the solid heat transfer members 108 can be maintained at a temperature that is lower than that of surfaces of the casting M3 in the vicinity of the solidification interface. The cooling medium that is blown out of the cooling nozzles 106 is blocked by the solid heat transfer members 108 and does not reach the retained molten metal M2. Thus, the retained molten metal M2 can be prevented from being swung.

The cooling parts 110 that arc shown in FIG. 3 and the cooling nozzles 106 that are shown in FIG. 4 may be used in combination. Also, cooling fins may be provided on surfaces of the solid heat transfer members 108 (especially, on the surfaces onto which the cooling medium from the cooling nozzles 106 is blown).

<Second Embodiment> FIG. 5 is an enlarged cross-sectional view that illustrates a configuration example of a free casting apparatus according to a second embodiment. Compared to the free casting apparatus that is shown in FIG. 1, the free casting apparatus that is shown in FIG. 5 further includes a metal wool 111 that is made of a metal that has high thermal conductivity, such as copper or a copper alloy, as a part of each solid heat transfer member 108. Because the other configurations of the free casting apparatus that is shown in FIG. 5 are the same as those of the free casting apparatus that is shown in FIG. 1, their description is omitted.

Because the free casting apparatus according to this embodiment includes a metal wool 111 as a part of each solid heat transfer member 108, the solid heat transfer members 108 and the casting M3 can be held in contact with each other more easily and the friction resistance between the solid heat transfer member 108 and the casting M3 can be reduced more easily.

In addition, in the free casting apparatus according to this embodiment, the contact area between the solid heat transfer members 108 and the casting M3 can be increased. Thus, the free casting apparatus according to this embodiment can cool the casting M3 more quickly. This allows the speed at which the starter ST is pulled up to be further increased.

The free casting apparatus according to this embodiment may further include a cooling part 110 in each solid heat transfer member 108 as shown in FIG. 6, may further include cooling nozzles 106 that blow a cooling medium onto the upper surfaces of the solid heat transfer members 108 as shown in FIG. 7, or may include the cooling parts 110 and the cooling nozzles 106 in combination. The cooling parts 110 may be routed through the metal wools 111. Alternatively, a cooling medium may be directly blown onto the metal wools 111. In these cases, the cooling rate of the casting M3 can be improved.

<Third Embodiment> FIG. 8 is an enlarged cross-sectional view that illustrates a configuration example of a free casting apparatus according to a third embodiment. Compared to the free casting apparatus that is shown in FIG. 1, the free casting apparatus that is shown in FIG. 8 includes solid heat transfer members 108 a in place of the solid heat transfer members 108. Because the other configurations of the free casting apparatus that is shown in FIG. 8 are the same as those of the free casting apparatus that is shown in FIG. 1, their description is omitted.

Each solid heat transfer member 108 a has the shape of a circular column that is rotatable in the direction in which the casting M3 is pulled up (in a vertical direction). Thus, because the solid heat transfer members 108 a rotate as the casting M3 is pulled up, the friction resistance between the solid heat transfer members 108 a and the casting M3 can be further reduced.

The free casting apparatus according to this embodiment may further include a cooling part 110 in each solid heat transfer member 108 a as shown in FIG. 9, may further include cooling nozzles 106 that blow a cooling medium onto the upper surfaces of the solid heat transfer members 108 a as shown in FIG. 10, or may include the cooling parts 110 and the cooling nozzles 106 in combination. In these cases, the cooling rate of the casting M3 can be improved.

<Fourth Embodiment> FIG. 11 is an enlarged cross-sectional view that illustrates a configuration example of a free casting apparatus according to a fourth embodiment. Compared to the free casting apparatus that is shown in FIG. 8, the free casting apparatus that is shown in FIG. 11 further includes a metal wool 111 that is made of a metal that has high thermal conductivity, such as copper or a copper alloy, as a part of each solid heat transfer member 108 a. Because the other configurations of the free casting apparatus that is shown in FIG. 11 are the same as those of the free casting apparatus that is shown in FIG. 8, their description is omitted.

Because the free casting apparatus according to this embodiment includes a metal wool 111 as a part of each solid heat transfer member 108 a, the solid heat transfer members 108 a and the casting M3 can he held in contact with each other more easily and the friction resistance between the solid heat transfer member 108 a and the casting M3 can be reduced more easily.

In addition, in the free casting apparatus according to this embodiment, the contact area between the solid heat transfer members 108 a and the casting M3 can be increased. Thus, the free casting apparatus according to this embodiment can cool the casting M3 more quickly. This allows the speed at which the starter ST is pulled up to be further increased.

The free casting apparatus according to this embodiment may further include a cooling part 110 in each solid heat transfer member 108 a as shown in FIG. 12, may further include cooling nozzles 106 that blow a cooling medium onto the upper surfaces of the solid heat transfer members 108 a as shown in FIG. 13, or may include the cooling parts 110 and the cooling nozzles 106 in combination. The cooling parts 110 may be routed through the metal wools 111. Alternatively, a cooling medium may be directly blown onto the metal wools 111. In these cases, the cooling rate of the casting M3 can be improved.

<Fifth Embodiment> FIG. 14 is an enlarged cross-sectional view that illustrates a configuration example of a free casting apparatus according to a fifth embodiment. Compared to the free casting apparatus that is shown in FIG. 8, the free casting apparatus that is shown in FIG. 14 includes supporting members 109 a in place of the supporting members 109, which are elastic members, such as springs.

Each supporting member 109 a supports a solid heat transfer member 108 a in a suspended fashion. Each solid heat transfer member 108 a is held in contact with a surface of the casting M3 by its own weight. In other words, the supporting members 109 a bias the solid heat transfer member 108 a into contact with a surface of the casting M3.

FIG. 15 is a cross-sectional view that is taken along the line II-II in FIG. 14. As shown in FIG. 15, a cooling part 110 through which a cooling medium W1, such as water, is circulated is provided in each solid heat transfer member 108 a.

FIG. 16 is an enlarged cross-sectional view of the cooling part 110 that is shown in FIG. 14. As shown in FIG. 16, the cooling part 110 has buckets 112, for example, that scoop up the cooling medium W1 as the solid heat transfer member 108 a rotate. In this case, because the cooling medium W1 can be scooped up (lifted up) to the location where the solid heat transfer member 108 a contacts the casting M3 even when the amount of the cooling medium W1 is small (the surface level of the cooling water is low), the cooling rate of the casting M3 can be improved. In addition, the buckets 112 can also function as cooling fins.

As described above, in the free casting apparatuses according to the first to fifth embodiments, the casting M3 is cooled not by a cooling medium that is blown out of a cooling nozzle but by contacting it with the solid heat transfer members 108 (108 a). Thus, the free casting apparatus according to the first to fifth embodiments can cool the casting M3 quickly without swinging the retained molten metal M2. This allows the speed at which the starter ST is pulled up to he increased.

While a case where a casting with the shape of a rectangular column (rectangular column-shaped casting) is cast is described as an example in the above embodiments, the present invention is not limited thereto. The present invention is also applicable in producing a casting with another shape, such as the shape of a rectangular tube, circular column or circular tube. A case where a casting with the shape of a rectangular tube is cast is briefly described below with reference to FIG. 17 and FIG. 18.

FIG. 17 is a cross-sectional view that illustrates another configuration example of a free casting apparatus according to the present invention. The free casting apparatus that is shown in FIG. 17 includes an internal shape-defining member 102 c in addition to the external shape-defining member 102 a.

The internal shape-defining member 102 c defines the internal shape of the casting M3 to be cast, and the external shape-defining member 102 a defines the external shape of the casting M3 to be cast. The casting M3 that is shown in FIG. 17 is a tubular hollow casting (in other words, a pipe) that has a tubular shape in its horizontal cross-section (which is hereinafter referred to as “transverse cross-section”). More specifically, the internal shape-defining member 102 c defines the internal shape of the transverse cross-section of the casting M3, and the external shape-defining member 102 a defines the external shape of the transverse cross-section of the casting M3.

FIG. 18 is a plan view of the internal shape-defining member 102 c and the external shape-defining member 102 a. The cross-sectional view of the internal shape-defining member 102 c and the external shape-defining member 102 a in FIG. 17 corresponds to a cross-sectional view that is taken along the line III-III in FIG. 18. As shown in FIG. 18, the external shape-defining member 102 a has a rectangular planar shape, for example, and has a square opening at its center. The internal shape-defining member 102 c has a rectangular planar shape, and is located at the center of the opening of the external shape-defining member 102 a. The gap between the internal shape-defining member 102 c and the external shape-defining member 102 a defines a molten metal passing part 102 b through which the molten metal is passed. A shape-defining member 102 is constituted of the internal shape-defining member 102 c, the external shape-defining member 102 a, and the molten metal passing part 102 b as described above. With this configuration, a casting with the shape of a rectangular tube can be cast.

The present invention is not limited to the above embodiments, and may be modified as needed without departing from its scope. For example, the above-mentioned configuration examples may be used in combination. 

1. An upward continuous casting apparatus, comprising: a retaining furnace that retains a molten metal; a draw-out part that draws out the molten metal from a melt surface of the molten metal that is retained in the retaining furnace; a shape-defining member that defines a cross-sectional shape of a casting to be cast by applying an external force to a retained molten metal which is a unsolidified molten metal that has been drawn out by the draw-out part, the shape-defining member being located in the vicinity of the melt surface; and a solid heat transfer member that is placed to contact a surface of the casting that is formed by solidification of the retained molten metal.
 2. The upward continuous casting apparatus according to claim 1, wherein the solid heat transfer member is placed to contact a surface of the casting in the vicinity of an interface between the retained molten metal and the casting.
 3. The upward continuous casting apparatus according to claim 1, wherein the solid heat transfer member has a shape that corresponds to the cross-sectional shape of the casting at a portion of the solid heat transfer member placed into contact with the casting.
 4. The upward continuous casting apparatus according to claim 1, wherein the solid heat transfer member has a curved surface shape at a portion of the solid heat transfer member placed into contact with the casting.
 5. The upward continuous casting apparatus according to claim 1, wherein the solid heat transfer member has the shape of a circular column that is rotatable in a direction in which the casting is pulled up.
 6. The upward continuous casting apparatus according to claim 5, further comprising a cooling part through which cooling water is circulated in the solid heat transfer member, wherein the cooling part has a bucket that scoops up the cooling water as the solid heat transfer member rotates.
 7. The upward continuous casting apparatus according to claim 1, further comprising a cooling part through which a cooling medium is circulated in the solid heat transfer member.
 8. The upward continuous casting apparatus according to claim 1, further comprising a cooling nozzle that blows a cooling medium onto an upper surface of the solid heat transfer member.
 9. The upward continuous casting apparatus according to claim 1, further comprising a supporting member that biases the solid heat transfer member into contact with a surface of the casting.
 10. The upward continuous casting apparatus according to claim 9, wherein the supporting member is a spring.
 11. The upward continuous casting apparatus according to claim 1, wherein the solid heat transfer member has a metal wool at a portion of the solid heat transfer member placed into contact with the casting.
 12. The upward continuous casting apparatus according to claim 1, wherein the solid heat transfer member is made of copper or a copper alloy.
 13. The upward continuous casting apparatus according to claim 1, further comprising an actuator that moves the solid heat transfer member in response to a movement of the shape-defining member.
 14. The upward continuous casting apparatus according to claim 1, wherein, when a starter is pulled up from the melt surface, the molten metal is pulled up from the melt surface following the starter by a surface film or surface tension thereof to form a retained molten metal, a shape is imparted to the retained molten metal by the shape-defining member, and the retained molten metal is solidified from top to bottom to form a casting.
 15. An upward continuous casting method, comprising: placing a shape-defining member that defines a cross-sectional shape of a casting to be cast in the vicinity of a melt surface of a molten metal that is retained in a retaining furnace; pulling up the molten metal through the shape-defining member; and cooling the casting by placing a solid heat transfer member into contact with a surface of the casting that is formed by solidification of the molten metal that has been passed through the shape-defining member:
 16. The upward continuous casting method according to claim 15, wherein the solid heat transfer member is placed into contact with a surface of the casting in the vicinity of a interface between a retained molten metal which is a unsolidified molten metal that has been pulled up and the casting.
 17. The upward continuous casting method according to claim 15, wherein the solid heat transfer member has a shape that corresponds to the cross-sectional shape of the casting at a portion of the solid heat transfer member placed into contact with the casting.
 18. The upward continuous casting method according to claim 15, wherein the solid heat transfer member has a curved surface shape at a portion of the solid heat transfer member placed into contact with the casting.
 19. The upward continuous casting method according to claim 15, wherein the solid heat transfer member has the shape of a circular column that is rotatable in a direction in which the casting is pulled up.
 20. The upward continuous casting method according to claim 19, wherein a cooling part through which cooling water is circulated is further provided in the solid heat transfer member, and a bucket that scoops up the cooling water as the solid heat transfer member rotates is provided in the cooling part.
 21. The upward continuous casting method according to claim 15, wherein a cooling part through which a cooling medium is circulated is further provided in the solid heat transfer member.
 22. The upward continuous casting method according to claim 15, wherein a cooling nozzle that blows a cooling medium onto an upper surface of the solid heat transfer member is further provided.
 23. The upward continuous casting method according to claim 15, wherein a supporting member that biases the solid heat transfer member into contact with a surface of the casting is further provided.
 24. The upward continuous casting method according to claim 23, wherein the supporting member is a spring.
 25. The upward continuous casting method according to claim 15, wherein a metal wool is further provided at a portion of the solid heat transfer member placed into contact with the casting.
 26. The upward continuous casting method according to claim 15, wherein the solid heat transfer member is made of copper or a copper alloy.
 27. The upward continuous casting method according to claim 15, wherein the solid heat transfer member is moved in response to a movement of the shape-defining member.
 28. The upward continuous casting method according to claim 15, wherein, when a starter is pulled up from the melt surface, the molten metal is pulled up from the melt surface following the starter by a surface film or surface tension thereof to form a retained molten metal, a shape is imparted to the retained molten metal by the shape-defining member, and the retained molten metal is solidified from top to bottom to form a casting. 